Chemistry, asked by Anshuman1382, 1 year ago

A 4.00 g sample of an anhydrous group 2 metal nitrate is heated strongly until there is no further change. A solid residue of mass 1.37 g is formed. Which metal is present?

Answers

Answered by abhi178
17
answer : Ca

explanation : group II metal is divalent. so, chemical formula of metal nitrate should be M(NO_3)_2, where M belongs to group II.

now, metal nitrate is heated strongly and as solid residue of mass 1.37g is formed. this solid residue is not other than metal.

for better understanding, chemical reaction is ...

2M(NO_3)_2\rightarrow 2MO+2NO_2+3O_2

here, it is clear 2 mole of metal nitrate forms 2 mole of metal oxide solid.

so, 1 mole of metal nitrate forms 1 mole of metal oxide solid.

or, (M + 124) g metal nitrate forms (M + 16)g of metal oxide

or, 4g of metal nitrate forms (M + 16)/(M + 124) × 4 = 1.37g

so, (M + 16)/(M + 124) = 1.37

hence, M ≈ 40 g/mol

so, atomic mass of metal is 40g/mol so, metal is not other than calcium.
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